Shark Sightings Rattle Nerves Along Cape Cod Coast

A pair of great white shark sightings off the coast of Cape Cod in recent days has swimmers heading for the safety of the beach.

The ominous dorsal fin lurking off Nauset Beach in Orleans, Mass., was enough for officials to temporarily close the popular swim spot on Sunday, just days after another great white shark sighting in the Cape Cod area.

"It was reported to me that our senior lifeguard had spotted a dorsal fin about 150 yards east of the public bathing beach. He estimated it to be 12 to 13 feet in length," Dawson Farber, harbormaster in Orleans, told ABCNews.com.

Lifeguards ordered swimmers out of the water at 10:15 a.m. and cordoned off a quarter mile swath of the beach, Farber said. The waters were reopened to the public an hour later, he said, after there were no additional sightings in the area.

"We had a number of sightings last year, some confirmed, some unconfirmed," Farber said. "We are operating under the assumption these animals are here to stay."

The first shark sighting of the season occurred on Friday when a 13-foot great white shark was tagged off the coast of Chatham, about nine miles from where the second sighting occurred on Sunday. It was unclear whether the same shark was spotted again on Sunday, since Farber said the lifeguard was unable to tell whether the shark had a tag on its dorsal fin.

Sightings of the predatory creatures, which rip their pray into pieces that they then swallow whole, were also common in the area last summer.

In July 2012, a man was attacked in by what is believed to be a great white shark in the waters off Ballston Beach in Truro, Mass. Police said Chris Meyers was bit in both legs below the knees in possibly one single, crushing blow.

"I think it is important to at least keep the public informed and remind them these animals are in our waters. We're not trying to instill fear or any sense of panic," Farber said. "We are their guests, not the other way around."